Electric contact device for automatic operation of mechanisms



Deb. 25, 1934. v v H. H. DODGE 1,935,340

ELECTRIC CONTACT DEVICE FOR AUTOMATIC OPERATION OF MECHANISMS Filed Feb.20, 1935 2 Sheets-Sheet 1 l2 l0 I 3 JYEDOCZ e nvezz r Dec. 25, 1934. H.H, DODGE 1,985,340

ELECTRIC CONTACT DEVICE FOR AUTOMATIC OPERATION OF MECHANISMS Filed Feb.20, 1935 2 Sheets-Sheet 2 3/ 29- Bl-METT/IL/C I59. 4

/7 H407 comma/v nyozmme I J v 42 Q '1 2G 22 A I I I I l I )7. 17. Dodge.bzventaz' I I Attorney Patented Dec. 25, 1934 PATENT OFFICE ELECTRICCONTACT DEVICE FOR AUTO- MATIC OPERATION OF MECHANISMS .Harry H. Dodge,Williamsport, Pa., assignor to J. H. McCormick & 00., Williamsport,Pa... a corporation of Pennsylvania Application February 20, 1933,Serial No. 657,700

7 Claims.

This invention relates to electric contact devices for automaticoperation of mechanisms and has for its object to provide a constructionwhich is compact, cheap to manufacture, simple in 5 operation, and moreefiicient in use than those heretofore proposed. a

With these and other objects in view the invention resides in the noveldetails of construction and arrangements of parts as will appear morefully hereinafter and be particularly pointed out in the claims.

Referring to the accompanying drawings forming a part of thisspecification in which like numerals designate like parts in allthe'views,-

Fig. 1 is a face view of the switch block;

Fig. 2 is a bottom plan view of the parts shown in Fi 1;

Fig. 3 is a vertical sectional view taken as on the line 3-3 of Fig. 1and looking in the direction of the arrows;

Fig. 4 is a diagrammatic illustration of a pilot burner assembly withwhich this device is intended for use; and

Fig. 5 is a' wiring diagram of the apparatus.

This invention is particularly adapted for use with burners utilizinggas or other fuel and wherein there is employed a pilot burner which isintended to burn constantly and which furnishes the means for ignitingthe fuel when the burner proper is automatically put in operation as aresult of temperature changes.

It is particularly adapted in such an assembly not only to automaticallycut off the flow of gas to the pilot burner and/ or the fuel burner whenthe pilot light goes out, but it also is adapted to control a circuit togive an alarm, either visual or audible, when said pilot light hasbecome extinguished, thereby notifying an attendant or other person ofthe state of pilot condition.

The device comprises a block 1 of electrical insulation upon which isintegrally or otherwise mounted a shelf 2, the latter disposed atsubstantially right angles to the formatio'n'of the block land extendingfrom a face thereof as clearly indicated in Fig. 3. Suitable openings 3are provided for bolts for securing the block to any suitable supportsuch as the plate 4 of the pilot burner assembly shown in Fig. 4. Acover 5is indicated in dot and dash lines in Fig. 2 which is secured inplace in any suitable manner such .as by the screws 6 threaded intobushings 'I moulded in the mounting block 1.

Thesh'elf 2 is drilled to receive a plurality of binding posts of whichpreferably there are four,

the-posts l0 and 11 beingused in a circuit associated with means forcutting off the flow of gas to the pilot when the pilot light has becomeextinguished, and the other pair of posts 12 and 13 being used in anindependent electric circuit associated with the alarm hereinbeforementioned. The binding posts and 11 are connected as shown to the pairof 'pilot contact strips 14 and 15 which are similar but oppositelyformed.

Each strip extends downwardly, having its lower end secured to themounting block 1 as by a rivet l6, and each strip has an arcuatelyformed edge facing the other strip so that, when the strips are inplace, these arcuate edges may circularly encompass the push rodassembly later to be described.

With reference to Fig. 5 it will be seen that the contact strip 14 isconnected as by the Wire 17 to a source of current, and that the othercontact strip 15 is connected as by the Wire 18 to said source with anysuitable mechanism generally indicated by the numeral 19 interposed inthe circuit, said mechanism adapted to operate a valve in the gas lineconnection to the pilot burner to reduce the flow of gas therethrough orto close said valve when the circuit is broken. The circuit in saiddiagram is shown in closed relation by virtue of a contact ring 20bridging the contact strips 14 and 15 and pressed against said strips bya light coil spring 21, in which relationship the pilot burner actuator1!) permits free flow of gas to the pilot.

The contact ring 20 is preferably stamped from sheet metal with itscentral portion pressed out of the plane of the ring proper so as toform a roundedor d0me-shapedcenter which is apertured to receivetherethrough the adjusting screw 22 which latter is provided with a kerf23 in the outer end thereof to receive the blade of an instrument forturning said screw. The edge portion of the ring is provided with aplurality of spaced pointed projections extending from a face of thering toward the faces of the pilot contact strips 14 and 15 to makebetter electrical contact therewith as well as to prevent sticking. Theinner end of the screw is threaded for a considerable distance andengages the adjusting block 24 which is of a length to pass completelythrough the mounting block 1. This adjusting block is formed with flatsides, being shown of square cross sectional shape in Fig. 1, to preventturning of said block but the opening therefor in the mounting block issuffioiently greater than the dimension of the adjusting block to permitready longitudinal movement of the latter in the former. Preferably theadjusting block is centrally drilled to provide a In other words, and aswill be clear from Fig,

4, the pilot burner has the thermal strip 29 close ly mounted adjacentthereto so that the heat of the flame of said pilot may flex the strip,expanding it to cause the free end of said strip to move away from thefixed end thereof.

contact with both pilot contact strips 14 and 15, thereby closing thecircuit hereinbefore described.

Also the spring 21 and ring 20 forcetheadjusting block 24 to the left asseen in Fig. 3, and this in turn permits the push rod 26 toextend-likewise to the left to keep its end 28 in contact with theheated or expanded thermal strip.

The adjusting screw 22 is turned by a suitable instrument to create thenecessary adjustment of these parts so that when the thermal strip is soexpanded, the contact ring 20 will close said circuit. 0n the otherhand, when'the pilot light goes out, the thermal strip will cool andtherefore will contract or flex in the opposite direction so that itsfree end will move toward its fixed end,

and this causes a reverse movement of the push rod which in turndisengages the contact ring 20 from the pilot contact strips 14 and 15,thereby opening said circuit. As hereinbefore stated; the spring 21 isof light construction, and therefore exerts no tension or pressure whichis greater than the tension created by the contracting thermal strip. 1

The block 1 has mounted thereupon a spring support, of general invertedU-shape as seen in Fig. 2, the ends of said support being secured tosaid block by a pair of identical bolts 35. The middle portion 36 ofthis support is therefore seen to be spaced considerably from the faceof the mounting block 1 by the standard portions 44 of said support.Said middle portion 36 has its center dished or bowed to provide adomeformanon similar to that of the contact-ring .20, the two domedportionsof these members'facing each other to provide seats forpositioning the spring 21, and the adjusting screw 22 has a sliding fitwithin an aperture in the dome portion 36.

It will be clearly seen from Fig. luthat this spring support is disposedobliquely on the face of the mounting block 1 to provideample clearancefor the alarm contact member 37, presently to be described. One of thebolts 35 secures one end of a bus bar or connection strip 38, the otherend of which is integrally secured to the binding post 13. The bindingpost 12 has rigidly secured theret one end of a second bus bar orconnection strip 39, the other end of which is secured by a bolt 40,carried by the mounting block 1, in metallic and electric contact withthe fixed end of the alarm contact member 37. 'I'hismember has its freeend disposed closely adjacent the contact ring 20 on the side thereofoppositeto the pilot contact strips 14 and 15 so that, when said ring ismoved a by the push rod 26, contact may be made with the end of saidmember. rigidity in this circuit closing contact, the member 37 isprovided with an appreciable arch as This permits I the light spring 21to force the ring 20 into- 2. Inan electric circuit breaker thecombination of a base of insulating material; a pair of when said rod ismoved in the other of its direc- In order that there be no through thealarm, generally indicated by the numeral 41, over the wire 42 throughthe alarm contact 27 into the ring 20 and thence through the spring 21into the spring support 36 and over the wire 43 back to the source.

It will thus be seen that the alarm contact 37 and the two pilot contactstrips 14 and 15 are each and all insulatedly mounted, not only withrespect to each other but with respect to the rest of the mechanism, andtherefore neither of the two circuits can be closed except when thecontact ring 20 is in one ofits two limiting positions. The wires 17,1-8, 42 and 43, have not been shown in Figs. 1, 2 and 3 for the sake ofclearness, but it will be readily understood how they will be connectedon the posts provided therefor by reference to the wiring diagram. 1

What is'claimed is:-,

1. In an electric circuit breaker thecombina tion of a base ofinsulating material; a pair .of

spaced contacts fixed upon one surface of said base; a rod reciprocablethrough said base between. said contacts, said rod moved in one of itsdirections by an external force; a metallic member carried by said rodand adjustable axially thereof, said member adapted to close said contacts when said rod is moved in .the other of its directions; a metallicguide bracket fixed to said base and slidingly receiving an end of saidrod; a spring disposed about said rod and electrically and operativelyconnecting said bracket and said member, said spring for moving the rodin said other of itsdirections; and a single contact fixed to said baseand having a free end disposed betweensaid member and said bracket, saidend spaced from the plane of the pair of contacts; and adapted to makecontact with said member upon movement of said rod under the urge of theexternal force.

spaced contacts having arcuate edge portions fixed upon one surface ofsaid base; a rod reciprocable through said base between the arcuatelyformed portions of said contacts, said rod moved in one of itsdirections by an external force; a

metallic member carried by said rod and adjustable axially thereof, saidmember having a circularedge portion adapted to contact and electricallyclose the arcuate portions of said contacts tions; a metallic guidebracket fixed to said base and slidingl receiving an end of said rod; a

to said base and having a free end disposed between saidmember and saidbracket, said end spaced from the plane of the pair of contacts; andadapted to make contact with said-member upon movement of said rod underthe urge of the external force. g

3. In an electric circuit breaker the combination of a base ofinsulating material; a pair of spaced contacts fixed upon one surface ofsaid base; a

rod reciprocable through said base between said contacts, said rod movedin one of its directions by an external force; a metallic member carriedby said rod and adjustable axially thereof, said member adapted to closesaid contacts when said rod is moved in the other of its directions; ametallic guide bracket substantially of U-shape fixed to said base, withthe bottom of the U straddling the pair of contacts as well as disposedsubstantially parallel to the plane of said contacts, and slidinglyreceiving an end of said rod; a spring disposed about said rod withinthe confines of the U-shaped bracket, and electrically and operativelyconnecting said bracket and said member, said spring for moving the rodin said other of its directions; and a single contact fixed to said baseand having a free end disposed between said member and the bottom of theU of said bracket, said end spaced from the plane of the pair ofcontacts; and adapted to make contact with said member upon movement ofsaid rod under the urge of the external force.

4. In an electric circuit breaker the combination of a base ofinsulating material; a pair of spaced contacts fixed upon one surface ofsaid base; a rod reciprocable through said base between said contacts,said rod moved in one of its directions by an external force; a metallicmember carried by said rod and adjustable axially thereof, said memberadapted to close said contacts when said rod is moved in the other ofits directions; a metallic guide bracket fixed to said base andslidingly receiving an end of said rod; a spring disposed about said rodand electrically and operatively connecting said bracket and saidmember, said spring for moving the rod in said other of its directions;and a single contact fixed at one end to said base, the remainder benthook-like in a direction away from the supporting surface of the baseand terminating in a free end disposed between said member and saidbracket, said end spaced from the plane of the pair of contacts; andadapted to make contact with said member upon movement of said rod underthe urge of the external force.

5. In an electric circuit breaker the combination of a base ofinsulating material; a pair of spaced contacts fixed upon one surface ofsaid base; a rod reciprocable through said base between said contacts,said rod moved in one of its directions by an external force; a metallicmember carried by said rod and adjustable axially thereof, said memberadapted to close said contacts when said rod is moved in the other ofits directions; a metallic guide bracket fixed to said base andslidingly receiving an end of said rod; a spring disposed about said rodand electrically and operatively connecting said bracket and saidmember, said spring for moving the rod in said other of its directions;and a single contact fixed at one end to said base, the remainder benthook like in a direction away from the supporting surface of the baseand terminating in a free resilient end disposed between said member andsaid bracket, said end spaced from the plane of the pair of contacts;and adapted to make contact with said member upon movement of said rodunder the urge of the external force.

6. In an electric circuit breaker the combination of a base ofinsulating material; a pair of spaced contacts carried by said base; arod reciprocable between said contacts, said rod moved in one of itsdirections by an external force; a metallic member carried by said rodand adapted to close said contacts when said rod is moved in the otherof its directions; a metallic guide bracket slidingly receiving an endof said rod; a spring electrically and operatively connecting saidbracket and said member, said spring for moving the rod in said other ofits directions; and a single contact fixed to said base and having afree end disposed between said member and said bracket, said end spacedfrom the plane of the pair of contacts; and adapted to make contact withsaid member upon movement of said rod under the urge of the externalforce.

'7. In an electric circuit breaker the combination of a base ofinsulating material; a pair of spaced contacts carried by said base; arod reciprocable between said contacts, said rod moved in one of itsdirections by an external force; a metallic member carried by said rodand adapted to close said contacts when said rod is moved in the otherof its directions; a metallic guide bracket slidingly receiving an endof said rod; a spring electrically and operatively connecting saidbracket and said member, said spring for moving the rod in said other ofits directions; and a single contact fixed at one end to said base, theremainder bent hook-like in a direction away from the supporting surfaceof the base and terminating in a free resilient end disposed betweensaid member and said bracket, said end spaced from the plane of the pairof contacts; and adapted to make contact with said member upon movementof said rod under the urge of the external force.

HARRY H. DODGE.

